The purpose of this manuscript is to analyse the interventions of energy retrofit of a non-residential and historic building, through dynamic simulation by the use of the TRNsys code. The study is made up of some steps:

• the analysis of the building and utility data, including study of the installed equipment and analysis of energy bills;

• the survey of the real operating conditions;

• the selection and the evaluation of energy conservation measures;

• the identification of interventions of energy retrofit;

• TRNsys simulation of the effects of these interventions on the energy behaviour of the building.

The present paper aims to present the results of the study, to discuss the expected energy behaviour of the building and to comment on the options for introducing energy conservation techniques.